Ground Floor Insulation Between Joists

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Ground floor insulation between joists.

If the ground floor in question is of a suspended timber construction and whether this is a renovation or new build project then the insulation would normally be installed in the joist zone that is installed between the joists. Insulating under the floorboards on the ground floor will save you about 40 a year. Timber floors can be insulated by lifting the floorboards and laying mineral wool insulation supported by netting between the joists. The fiberglass will also need to be secured in place using wire mesh twine wood laths or other securing methods which can be an intensive project that adds to the overall cost.

Design considerations such as existing ground conditions the presence of radon gas or methane gas and the intended use of the building are among the factors that will dictate the choice of ground floor and also the insulation used within them. This floor insulation method is commonly used for upgrading the thermal performance of existing timber floors as it has no impact on floor levels. At least 25mm of the joist must be left exposed to ensure air circulation. For concrete floors either above or below the floor or for timber joist floors between the joists.

Joist bays the open spaces between floor joists are prime hosts for insulation under specific circumstances. It is possible to achieve very high levels of thermal insulation in exposed upper floors. Now the free movement of air in the ventilated area between the ground and the floorboards ensured the timbers were not degraded in this way. The designer has a choice of where to position the insulation.

The simplest way of insulating suspended timber ground floors is to fit insulation boards between the joists and support battens. The insulation should be pushed tight to the underside of the floorboards. When the basement or crawl space has vents installed insulating joist bays. Ground floors are usually constructed as either solid ground floors or suspended ground floors.

A semi rigid material is generally best as it can be cut very slightly oversized and squeezed in between the floor joists thereby ensuring no draught causing gaps. The insulation should press right up against the floor between joists. However the new design technique created a different problem.